1. Field of the Invention
The present invention generally relates to an apparatus that removes an adhesive tape from a wafer ring.
2. Description of the Related Art
After a well-known wafer fabrication process is performed a semiconductor wafer is cut and separated (wafer sawing or wafer dicing) into individual semiconductor chips by a wafer sawing apparatus. The individual chips are then provided to a semiconductor packaging or assembly process that begin with a chip attaching process. Before the wafer sawing process, the wafer is typically attached to an adhesive tape.
As shown in FIG. 1, an adhesive tape 18 (xe2x80x9cwafer ring tapexe2x80x9d) is attached to the back surface of the wafer 12. The wafer ring tape 18 is also attached to a wafer ring 16 surrounding the wafer 12. The wafer ring 16 facilitates the handling of the wafer 12. The chips 14 can remain on the wafer ring tape 18 after the wafer sawing process. Each of the chips 14 is detached from the wafer ring tape 18 and then attached to a lead frame or another circuitry substrate. After all normal chips (good dies) are detached, defective chips 14 remaining on the wafer ring tape 18 are discarded together with the wafer ring tape 18. The wafer ring 16 is reused.
A conventional removal of the wafer ring tape and the defective chips is manually performed. However, this causes not only low productivity but also a strong possibility of accidents. In addition, the wafer ring may be damaged or deformed due to careless handling. There is also a possibility that the defective chips are not scrapped but flows out.
Accordingly, the present invention provides an apparatus for automatically removing a wafer ring tape, on which defective chips remain, from a wafer ring after normal chips are detached from the tape for the following chip attaching step in a semiconductor package assembly process.
The present invention can prevent an outflow of chips by crushing the chips simultaneously with removal of the wafer ring tape.
In a first aspect of the present invention, an apparatus for removing a wafer ring tape from a wafer ring includes a ring table, which supports a tape-adhered wafer ring in which the wafer ring tape is attached to the wafer ring. The apparatus further includes a detaching head that is positionable above the ring table and movable to detach the wafer ring tape from the wafer ring. The apparatus still further includes a blocking pin that is disposed under the ring table to support the wafer ring tape detached from the wafer ring. In addition, the apparatus includes a pair of compressing plates that are disposed under the ring table to compress the wafer ring tape supported by the blocking pin.
Preferably, the apparatus may further include a loading member that is disposed near the ring table to load the tape-adhered wafer ring onto the ring table. The apparatus may further include an unloading member that is disposed near the ring table to unload the wafer ring from the ring table. The apparatus may also include a scrap box that is disposed under the compressing plates to receive the pressed and crushed wafer ring tape. The apparatus may further include a ring box that is disposed near the ring table to receive the wafer ring from which the wafer ring tape is removed.
In another aspect of the present invention, the apparatus for removing a wafer ring tape, on which defective chips remain, from a wafer ring, includes a ring table for supporting a wafer ring assembly in which the wafer ring tape is attached to the wafer ring. The apparatus further includes a detaching head capable of moving vertically, which is disposed above the ring table. The apparatus still further includes a pressing shaft capable of moving vertically separately from the detaching head, which is disposed inside the detaching head. The apparatus further also includes a pair of compressing plates capable of moving horizontally, which are disposed under the ring table. The apparatus further includes a blocking pin capable of moving horizontally, which is disposed in either or both of the compressing plates. In the apparatus, the detaching head moves downwardly and then detaches the wafer ring tape from the wafer ring. In addition, the pressing shaft moves downwardly and then pushes downwardly the detached wafer ring tape so that the wafer ring tape may be folded and temporarily suspended on the blocking pin. Furthermore, the compressing plates press together the folded wafer ring tape and then crush any defective chips that remain on the wafer ring tape.
The apparatus may further include a loading member disposed near the ring table and capable of loading the wafer ring assembly onto the ring table. The apparatus may further include an unloading member disposed near the ring table and capable of unloading the wafer ring from the ring table. The apparatus may also include a scrap box disposed under the compressing plates and capable of receiving the wafer ring tape that has been pressed and crushed by the compressing plates. Also, the apparatus may include a ring box disposed near the ring table and capable of receiving the wafer ring from which the wafer ring tape is removed. In the apparatus, the detaching head may have a cylindrical outer frame forming an inner space, and the cylindrical outer frame may have an outside diameter substantially equal to but less than an inside diameter of the wafer ring.
In still another aspect of the present invention, the apparatus includes a wafer cassette containing a plurality of wafer ring assemblies, each having the wafer ring and the wafer ring tape attached thereto. The apparatus further includes a loading conveyor for supplying the wafer cassette, and a rotatable plate disposed near the loading conveyor to receive the wafer cassette thereon from the loading conveyor and being capable of moving vertically and rotatively. The apparatus also includes a slide disposed close to the rotatable plate to facilitate discharge of the wafer ring assembly from the wafer cassette while the wafer cassette inclines toward the slide by rotation of the rotatable plate; a ring stand disposed near the slide to receive the wafer ring assembly thereon through the slide from the wafer cassette, and a loading picker positionable above the ring stand to move vertically and horizontally to transfer the wafer ring assembly on the ring stand to a new position.
In addition, the apparatus includes a ring table disposed near the loading picker to receive and support the wafer ring assembly transferred by the loading picker, a detaching head disposed above the ring table to move downwardly to detach the wafer ring tape from the wafer ring in the wafer ring assembly; a pressing shaft disposed inside the detaching head to move downwardly separately from the detaching head to fold the detached wafer ring tape, a blocking pin disposed under the ring table to temporarily support the folded wafer ring tape, and a pair of compressing plates disposed under the ring table to press together the wafer ring tape suspended on the blocking pin and crush the defective chips staying on the wafer ring tape.
The apparatus may further include an unloading conveyor disposed near the rotatable plate to unload the wafer cassette, in which a discharge of the wafer ring assembly is finished, from the rotatable plate. The apparatus may also include an unloading picker disposed near the ring table to unload the wafer ring from the ring table. In the apparatus, the ring table may move between the loading picker and the detaching head. In addition, the apparatus may include a scrap box disposed under the compressing plates to receive the wafer ring tape having been pressed and crushed by the compressing plates. The apparatus may additionally include a ring box disposed near the ring table to receive the wafer ring from which the wafer ring tape is removed. In the apparatus, the detaching head may have a cylindrical outer frame forming an inner cylindrical space, and the cylindrical outer frame may have an outside diameter substantially equal to but less than an inside diameter of the wafer ring.